Competition for the Nutrients between Sunflower (Helianthus annuus L.) and Associated Weeds during Spring Season
Abstract
A field experiment was carried out to assess the nutrienl uptake pattern by sunflower and associated weeds during spring season. Nutrient (N, P and K) content in weeds was greater at their younger stages and decreased towards maturity. Under unweeded control treatment, weeds removed 29.1 kg N, 2.9 kg P and 26.3 kg K/ha out of which Heliotropium eichwaldi Sed ex. DC mined 40.7% N (11.9 kg/ha), 38.0% P (1.1 kg/ha) and 38.4% K (10.1 kg/ha). The crop with season-long weed infestation removed 124.2 kg N, 49.9 kg P and 129.2 kg K/ha of total N, P and K, respectively, as against 160.5 kg N, 66.3 kg P and 171.0 kg K/ha for weed free check treatment.
